Odontolabis cuvera can reach a length (mandibles included) of about in male, of about in females. Moreover, males have a conspicuously elongated and large pair of mandibles. The basic color of the body is black. Elytra have broad orange margins on the outer edge. The female closely resembles the male in coloration but it lacks long mandibles. The males have also three morphological forms with variations in the size of their mandibles. These three alternative
phenotypes (male
trimorphism) in the types of male weapons are considered conditional reproductive strategies. In Lucanidae, there has only been two species described with this trimorphic characteristic as of 2017, with the other one being
Dorcus rectus. In the subspecies
Odontolabis cuvera sinensis elytra are almost completely black, with a small orange border. These beetles can reach a length of about . ==Life cycle==